1. Field
The present invention relates generally to cellular communication systems, and more specifically, to a method and apparatus for managing multi-carrier communications.
2. Background
Global System for Mobile Communication (GSM) cellular communication systems provide communication services to mobile and portable devices through an arrangement of base stations. In GSM systems, frames of timeslots and radio blocks are transmitted and received at the mobile station using time division multiplexing. Although GSM systems originally provided voice communication services, GSM systems have evolved to provide data communication services as well. Standards such as general packet radio service (GPRS) and Enhanced Data for Global Evolution (EDGE) further define the protocols for data communication within GSM based systems. The access terminals, also sometimes referred to as mobile devices, portable devices and by other names, communicate over channels in the uplink and the downlink directions. In order to increase performance, some access terminals utilize receive diversity techniques where two or more antennas are used to receive signals transmitted on a single channel. Due to differences between the antennas such as, for example, antenna position, at least some of the incoming signals can be received at a higher quality. For example, due to multi-fading characteristics of the communication path, multiple signals may destructively combine at one antenna and constructively combine at another antenna. By using receive diversity, however, chances increase to receive a higher quality signal. In some receiver diversity cases the signals from multiple antennas are combined to increase the signal quality.
As GSM systems evolve to providing increased data and voice services, the need for bandwidth and system capacity increases. In a multi-carrier communication system, signals are transmitted using multiple channels at different carrier frequencies. The receiver simultaneously receives the multiple channels through multiple antennas resulting in an increased overall bandwidth. Conventional systems do not include a method for utilizing multiple antennas for diversity and multi-channel communications in a single access terminal.
Therefore, there is need for an apparatus and method for managing multi-carrier communication in a GSM communication system.